Investment Protection with the Arista 7500 Series!

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1 Investment Protection with the Arista 7500 Series Introduction Arista Networks award-winning Arista 7500 series was introduced in April 2010 as a revolutionary switching platform, which maximized data center performance, efficiency and overall network reliability. It set the benchmark for switching performance and was five times faster, one-tenth the power draw and one-half the footprint compared to other modular data center switches from other networking vendors. Just three years later, the introduction of the Arista 7500E series linecards and fabric modules for the existing Arista 7500 switch delivers a three-fold increase in density and performance with no sacrifices on functionality, table sizes or buffering with a new industry-leading bench-mark of 1,152 x 10GbE, 288 x 40GbE or 96 x 100GbE in the same quarter-rack 11RU chassis. This whitepaper details the investment protection capabilities of the new Arista 7500 E-Series linecards and fabrics and how they utilize the existing Arista 7500 chassis and interoperate with the existing Arista 7500 linecards and fabric modules. Investment Protection Summary Where many vendors promise investment protection but don t deliver (or only provide ships in the night which means can coexist in the same chassis but not forward between one another ), the Arista 7500 series delivers complete interoperability and investment protection across all components that make up an Arista 7500 series switch: There is no change to the chassis or power-supplies Upgrading a first-generation Supervisor to a second-generation Supervisor-E is optional (note: Supervisor-E offers a more than three-fold increase in switch control-plane performance, so it may be desirable to upgrade) Mixing/matching first and second generation linecard modules with distributed data-plane forwarding is supported First-generation linecard modules are forward compatible with second-generation fabric modules. Likewise, second-generation linecard modules are backward compatible with first-generation fabric modules. In addition to complete interoperability it s also possible to do an in-place upgrade from first-generation to second-generation fabric modules without any disruption to data-plane forwarding. The investment protection provides a flexible migration and upgrade path for existing Arista 7500 switches and fulfils Arista s promise of future investment protection without expensive forklift upgrades. Arista Networks. All rights reserved. 1

2 Investment Protection with the Arista 7500 Series Upgrade considerations The following section contains details on interoperability and any steps that are required. Minimum EOS Software release A minimum software release of EOS must be running on a switch in order to support a secondgeneration linecard or fabric module. The minimum supported software release required for a Supervisor-E is EOS EOS was the first software release to support interoperability of first/second generation linecard modules/fabrics however we recommend EOS as the minimum release for interoperability in production environments. Most recent EOS 4.12 or later is recommended. Arista 7500 Chassis 7508E Series 7504E Series There is no change to the 7500 Series chassis. Designed with future proofing in mind, the existing Arista RU and RU chassis are capable of supporting the three-fold increase in performance and density enabled by second-generation 7500E linecard and fabric modules. Arista 7500 Power Supplies There is no change to the existing 2900W Power Supplies. Arista 7500 second-generation linecard and fabric modules provide a three-fold increase in the performance and density of ports within a single system while remaining within the same system-level power envelope. The end result is a two-thirds reduction in the power/port on what was already an industry-leading power consumption/port metric. The existing hot-swappable 2+2 redundant 2900W Gold Climate-rated Power Supplies (92% efficient) remain the same. Arista Networks. All rights reserved. 2

3 Arista 7500 Supervisor-E Investment Protection with the Arista 7500 Series Supervisor-E provides a more than three-fold increase in control-plane performance compared to the original Arista 7500 Supervisor (increased from a dual core to a hyper-threaded quad core), more memory (4GB to 16GB). Supervisor-E also has dual out-of-band management interfaces, a PPS clock input and an optional enterprise grade SSD for extensibility in addition to the capabilities of the 7500-Supervisor (or Supervisor-1). While upgrading a Supervisor-1 to Supervisor-E is optional, Arista recommends that Supervisor-E be used if expanding a chassis beyond the original G port maximum density supported on first-generation systems, or more than 64K hosts (MAC table, ARP entries, IPv6 neighbor entries) are required. [Note: It is not possible to run a system with Sup-1 and Sup-E in the same chassis. Supervisor upgrades will be disruptive.] Mixing first and second-generation Linecard Modules Mixing both first and second-generation linecard modules in the same system and forwarding between the different generation modules is supported. As the forwarding engine on second-generation linecard modules has larger tables and more capabilities compared to the forwarding engine on first-generation linecard modules, Arista EOS needs to know whether to limit the system capabilities to those of first-generation or not. This is controlled using the following commands: switch(config)# [no] platform sand forwarding mode [PetraA Arad] switch(config)# write memory switch(config)# reload A reboot is required after making changes to this setting for it to take effect. If forwarding compatibility is set to Arad mode than any first-generation linecard modules will be out-of-service and only second-generation linecard modules will operate. If set to PetraA mode then both first and second-generation linecard modules will function together however second-generation linecard modules will be capped to the capabilities of the first-generation forwarding engine and some features are disabled or restricted: MLAG peer-link member ports MUST be on first-generation linecards only. Using second-generation linecard ports or using a mix of both first and second-generation linecard ports for MLAG peer-link member ports is not supported and may cause mis-forwarding of packets MTU enforcement is not supported on mixed systems with first and second-generation linecards IPv6 ECMP is not supported on mixed systems with first and second-generation linecards PIM + MLAG is not supported on mixed systems with first and second-generation linecards ACL filtering capabilities are supported on mixed systems with first and second-generation linecards but with only the functionality available on first-generation linecards Second-generation linecards place some minor restrictions on VRRP/VARP compared to first-generation linecards, so care should be taken to ensure these constraints don t hinder the design in any way: VRRP VRIDs can only be assigned in a restricted range on second-generation linecard modules. This VRID assignment scheme therefore changes as a result of running in mixed mode Second-generation linecard modules don t allow VRRP and VARP to be configured on an interface at the same time. First-generation linecard modules allow this Arista Networks. All rights reserved. 3

4 Investment Protection with the Arista 7500 Series. The following table reflects the forwarding table/resource characteristics for each mode: Characteristic 7500 (PetraA) 7500E (Arad) MAC Table Size 16K 256K Max Host Route Prefixes 16K 128K Max IPv4 Route Prefixes 24K 64K Max IPv6 Route Prefixes 1K 12K+ Max Multicast Groups 16K 64K Max Egress Forwarding Entries / Forwarding 7.5K 30K Max LAG Groups 256 up to 1K Max LAG Members up to 16 member ports up to 32 member ports (initially) Max ECMP Fanout 16-way 32-way (64-way) MLAG Peer-Link physical interfaces Must be on 7500 linecards Must be on 7500E linecards PIM+MLAG Not supported Supported Features available on first-generation linecard modules that aren t available on secondgeneration Second-generation linecards place some minor restrictions on VRRP/VARP compared to first-generation linecards, so care should be taken to ensure these constraints don t hinder the design in any way: VRRP VRIDs can only be assigned in a restricted range on second-generation linecard modules. This VRID assignment scheme therefore changes as a result of running in mixed mode Second-generation linecard modules don t allow VRRP and VARP to be configured on an interface at the same time. First-generation linecard modules allow this Upgrading fabric modules from first-generation to second-generation Its possible for fabric modules to be upgraded in-place from first to second-generation without disruption to data-plane forwarding, however as the process involved in doing this is complex and requires very specific timing. Physical upgrades of this manner are also something that we cannot perform in our automated testing so our recommendation is that fabric module upgrades are not performed on a live system but instead on a powered-down system. If this is not desirable then please work with your Arista System er to work through the process. Once a system has been upgraded from first-generation to second-generation fabric modules, EOS assumes that you will continue to want to use second-generation fabric modules in future. If you intend to put firstgeneration fabric modules into the chassis in future then it will be necessary to configure EOS support and fe600 fabric compatibility should be enabled with: switch(config)# [no] platform sand compatibility fabric [fe600 fe1600] switch(config)# write memory Arista Networks. All rights reserved. 4

5 Investment Protection with the Arista 7500 Series First-generation linecard modules with second-generation fabric modules First-generation linecard modules operate seamlessly with second-generation linecard and fabric modules by default. No explicit configuration is necessary. Second-generation linecard modules with first-generation fabric modules Mixing second-generation linecard modules with first-generation fabric modules will limit the second-generation linecard modules to the hardware capabilities of the first-generation fabric. Some of these capability limits will be: 1. Fabric links will operate at 6.25 GHz rather than 11.5 GHz (approximately 45% lower fabric capacity) 2. The encoding will be 8b/9 rather than the more efficient 64b/66 (~approximately 9% less efficient) 3. Fabric maximum cell size will be limited to 128 bytes rather than 256 bytes (~5% less efficient) 4. At most 144 active fabric links to a linecard module rather than up to 192 active fabric links on the highest density modules (Up to 25% less performance) 5. Multicast expansion in the fabric will be limited to 16K groups rather than 64K groups Points (1) through (3) mean that the crossbar fabric bandwidth capacity available to second-generation modules on a per-fabric-link basis is approximately half what it would otherwise be with second-generation fabric modules. Point (4) limits the maximum performance on the highest density second-generation linecards. How this converts to real performance depends on the individual modules themselves and the grouping of ports across packet processors and the number of operational fabric links: DCS-7500E-36Q-LC (36 x QSFP+): o Port groups of 6 x QSFP+ ports (6x40G) per forwarding engine. Any 2 x QSFP+ (80 Gbps) could be used in each port group with N+1 fabric redundancy Up to 100 Gbps total bandwidth in each port group with no fabric redundancy (reduced performance on a fabric failure) PHYs Processor 4 PHYs Processor 5 Processor 6 PHYs DCS-7500E-72S-LC (48 x SFP+ and 2 x MPO/MTP): o Three port groups covering: SFP+ ports 1-20 SFP+ ports and MPO/MTP port 49/1-12 SFP+ ports and MPO/MTP port 50/1-12 Arista Networks. All rights reserved. 5

6 Investment Protection with the Arista 7500 Series Up to 120 Gbps in each port group with N+1 fabric redundancy Up to 150 Gbps in each port group with no fabric redundancy (reduced performance on a fabric failure) AOM AOM / /1-12 DCS-7500E-48S-LC (48 x SFP+): o Three port groups covering: SFP+ ports 1-16 SFP+ ports SFP+ ports Up to 120 Gbps in each port group with N+1 fabric redundancy Up to 150 Gbps in each port group with no fabric redundancy (reduced performance on a fabric failure) Arista Networks. All rights reserved. 6

7 Investment Protection with the Arista 7500 Series DCS-7500E-12CM-LC (12 x MPO/MTP): o Port groups of 2 x MPO/MTP ports (1x100G/3x40G/12x10G) per forwarding engine. Up to 80 Gbps could be used in each port group with N+1 fabric redundancy Up to 100 Gbps could be used in each port group with no fabric redundancy (reduced performance on a fabric failure) Processor 4 Processor 6 Processor 5 AOM AOM AOM AOM AOM AOM Conclusion Where many vendors continue to promise investment protection and don t deliver, the Arista 7500 series delivers complete forward and backward interoperability and investment protection across all components that make up an Arista 7500 series switch This investment protection provides a flexible migration and upgrade path for existing Arista 7500 switches and fulfils Arista s promise of investment protection, expanding the performance, without expensive forklift upgrades Arista Networks. All rights reserved. 7